[SPARC64]: Add mini-RTC driver for Starfire and SUN4V.

Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc64/kernel/time.c

@@ -30,6 +30,8 @@
 #include <linux/cpufreq.h>
 #include <linux/percpu.h>
 #include <linux/profile.h>
+#include <linux/miscdevice.h>
+#include <linux/rtc.h>
 
 #include <asm/oplib.h>
 #include <asm/mostek.h>
@@ -45,6 +47,7 @@
 #include <asm/smp.h>
 #include <asm/sections.h>
 #include <asm/cpudata.h>
+#include <asm/uaccess.h>
 
 DEFINE_SPINLOCK(mostek_lock);
 DEFINE_SPINLOCK(rtc_lock);
@@ -702,6 +705,14 @@ static u32 starfire_get_time(void)
 	return unix_tod;
 }
 
+static int starfire_set_time(u32 val)
+{
+	/* Do nothing, time is set using the service processor
+	 * console on this platform.
+	 */
+	return 0;
+}
+
 static u32 hypervisor_get_time(void)
 {
 	register unsigned long func asm("%o5");
@@ -731,6 +742,33 @@ static u32 hypervisor_get_time(void)
 	return 0;
 }
 
+static int hypervisor_set_time(u32 secs)
+{
+	register unsigned long func asm("%o5");
+	register unsigned long arg0 asm("%o0");
+	int retries = 10000;
+
+retry:
+	func = HV_FAST_TOD_SET;
+	arg0 = secs;
+	__asm__ __volatile__("ta	%4"
+			     : "=&r" (func), "=&r" (arg0)
+			     : "0" (func), "1" (arg0),
+			       "i" (HV_FAST_TRAP));
+	if (arg0 == HV_EOK)
+		return 0;
+	if (arg0 == HV_EWOULDBLOCK) {
+		if (--retries > 0) {
+			udelay(100);
+			goto retry;
+		}
+		printk(KERN_WARNING "SUN4V: tod_set() timed out.\n");
+		return -EAGAIN;
+	}
+	printk(KERN_WARNING "SUN4V: tod_set() not supported.\n");
+	return -EOPNOTSUPP;
+}
+
 void __init clock_probe(void)
 {
 	struct linux_prom_registers clk_reg[2];
@@ -1221,3 +1259,244 @@ static int set_rtc_mmss(unsigned long nowtime)
 		return retval;
 	}
 }
+
+#define RTC_IS_OPEN		0x01	/* means /dev/rtc is in use	*/
+static unsigned char mini_rtc_status;	/* bitmapped status byte.	*/
+
+/* months start at 0 now */
+static unsigned char days_in_mo[] =
+{31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
+
+#define FEBRUARY	2
+#define	STARTOFTIME	1970
+#define SECDAY		86400L
+#define SECYR		(SECDAY * 365)
+#define	leapyear(year)		((year) % 4 == 0 && \
+				 ((year) % 100 != 0 || (year) % 400 == 0))
+#define	days_in_year(a) 	(leapyear(a) ? 366 : 365)
+#define	days_in_month(a) 	(month_days[(a) - 1])
+
+static int month_days[12] = {
+	31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
+};
+
+/*
+ * This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
+ */
+static void GregorianDay(struct rtc_time * tm)
+{
+	int leapsToDate;
+	int lastYear;
+	int day;
+	int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
+
+	lastYear = tm->tm_year - 1;
+
+	/*
+	 * Number of leap corrections to apply up to end of last year
+	 */
+	leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400;
+
+	/*
+	 * This year is a leap year if it is divisible by 4 except when it is
+	 * divisible by 100 unless it is divisible by 400
+	 *
+	 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was
+	 */
+	day = tm->tm_mon > 2 && leapyear(tm->tm_year);
+
+	day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] +
+		   tm->tm_mday;
+
+	tm->tm_wday = day % 7;
+}
+
+static void to_tm(int tim, struct rtc_time *tm)
+{
+	register int    i;
+	register long   hms, day;
+
+	day = tim / SECDAY;
+	hms = tim % SECDAY;
+
+	/* Hours, minutes, seconds are easy */
+	tm->tm_hour = hms / 3600;
+	tm->tm_min = (hms % 3600) / 60;
+	tm->tm_sec = (hms % 3600) % 60;
+
+	/* Number of years in days */
+	for (i = STARTOFTIME; day >= days_in_year(i); i++)
+		day -= days_in_year(i);
+	tm->tm_year = i;
+
+	/* Number of months in days left */
+	if (leapyear(tm->tm_year))
+		days_in_month(FEBRUARY) = 29;
+	for (i = 1; day >= days_in_month(i); i++)
+		day -= days_in_month(i);
+	days_in_month(FEBRUARY) = 28;
+	tm->tm_mon = i;
+
+	/* Days are what is left over (+1) from all that. */
+	tm->tm_mday = day + 1;
+
+	/*
+	 * Determine the day of week
+	 */
+	GregorianDay(tm);
+}
+
+/* Both Starfire and SUN4V give us seconds since Jan 1st, 1970,
+ * aka Unix time.  So we have to convert to/from rtc_time.
+ */
+static inline void mini_get_rtc_time(struct rtc_time *time)
+{
+	unsigned long flags;
+	u32 seconds;
+
+	spin_lock_irqsave(&rtc_lock, flags);
+	seconds = 0;
+	if (this_is_starfire)
+		seconds = starfire_get_time();
+	else if (tlb_type == hypervisor)
+		seconds = hypervisor_get_time();
+	spin_unlock_irqrestore(&rtc_lock, flags);
+
+	to_tm(seconds, time);
+}
+
+static inline int mini_set_rtc_time(struct rtc_time *time)
+{
+	u32 seconds = mktime(time->tm_year + 1900, time->tm_mon + 1,
+			     time->tm_mday, time->tm_hour,
+			     time->tm_min, time->tm_sec);
+	unsigned long flags;
+	int err;
+
+	spin_lock_irqsave(&rtc_lock, flags);
+	err = -ENODEV;
+	if (this_is_starfire)
+		err = starfire_set_time(seconds);
+	else  if (tlb_type == hypervisor)
+		err = hypervisor_set_time(seconds);
+	spin_unlock_irqrestore(&rtc_lock, flags);
+
+	return err;
+}
+
+static int mini_rtc_ioctl(struct inode *inode, struct file *file,
+			  unsigned int cmd, unsigned long arg)
+{
+	struct rtc_time wtime;
+	void __user *argp = (void __user *)arg;
+
+	switch (cmd) {
+
+	case RTC_PLL_GET:
+		return -EINVAL;
+
+	case RTC_PLL_SET:
+		return -EINVAL;
+
+	case RTC_UIE_OFF:	/* disable ints from RTC updates.	*/
+		return 0;
+
+	case RTC_UIE_ON:	/* enable ints for RTC updates.	*/
+	        return -EINVAL;
+
+	case RTC_RD_TIME:	/* Read the time/date from RTC	*/
+		/* this doesn't get week-day, who cares */
+		memset(&wtime, 0, sizeof(wtime));
+		mini_get_rtc_time(&wtime);
+
+		return copy_to_user(argp, &wtime, sizeof(wtime)) ? -EFAULT : 0;
+
+	case RTC_SET_TIME:	/* Set the RTC */
+	    {
+		int year;
+		unsigned char leap_yr;
+
+		if (!capable(CAP_SYS_TIME))
+			return -EACCES;
+
+		if (copy_from_user(&wtime, argp, sizeof(wtime)))
+			return -EFAULT;
+
+		year = wtime.tm_year + 1900;
+		leap_yr = ((!(year % 4) && (year % 100)) ||
+			   !(year % 400));
+
+		if ((wtime.tm_mon < 0 || wtime.tm_mon > 11) || (wtime.tm_mday < 1))
+			return -EINVAL;
+
+		if (wtime.tm_mday < 0 || wtime.tm_mday >
+		    (days_in_mo[wtime.tm_mon] + ((wtime.tm_mon == 1) && leap_yr)))
+			return -EINVAL;
+
+		if (wtime.tm_hour < 0 || wtime.tm_hour >= 24 ||
+		    wtime.tm_min < 0 || wtime.tm_min >= 60 ||
+		    wtime.tm_sec < 0 || wtime.tm_sec >= 60)
+			return -EINVAL;
+
+		return mini_set_rtc_time(&wtime);
+	    }
+	}
+
+	return -EINVAL;
+}
+
+static int mini_rtc_open(struct inode *inode, struct file *file)
+{
+	if (mini_rtc_status & RTC_IS_OPEN)
+		return -EBUSY;
+
+	mini_rtc_status |= RTC_IS_OPEN;
+
+	return 0;
+}
+
+static int mini_rtc_release(struct inode *inode, struct file *file)
+{
+	mini_rtc_status &= ~RTC_IS_OPEN;
+	return 0;
+}
+
+
+static struct file_operations mini_rtc_fops = {
+	.owner		= THIS_MODULE,
+	.ioctl		= mini_rtc_ioctl,
+	.open		= mini_rtc_open,
+	.release	= mini_rtc_release,
+};
+
+static struct miscdevice rtc_mini_dev =
+{
+	.minor		= RTC_MINOR,
+	.name		= "rtc",
+	.fops		= &mini_rtc_fops,
+};
+
+static int __init rtc_mini_init(void)
+{
+	int retval;
+
+	if (tlb_type != hypervisor && !this_is_starfire)
+		return -ENODEV;
+
+	printk(KERN_INFO "Mini RTC Driver\n");
+
+	retval = misc_register(&rtc_mini_dev);
+	if (retval < 0)
+		return retval;
+
+	return 0;
+}
+
+static void __exit rtc_mini_exit(void)
+{
+	misc_deregister(&rtc_mini_dev);
+}
+
+
+module_init(rtc_mini_init);
+module_exit(rtc_mini_exit);